Female Athletes: Know the Score on Your Body

More women and girls than ever before take part in sports and other forms of exercise.

"At the same time, the speed, contact, and intensity of sport and exercise have increased, so more and more women are getting injured," says Alison Toth, M.D., a women's sports medicine specialist in Durham, N.C.

Active women face special risks. Here's a prime example: Women are two to 10 times more likely than men to suffer knee injuries of the anterior cruciate ligament (ACL), which helps link your upper and lower leg bones, Dr. Toth says. Among the highest-risk sports: basketball, soccer, field hockey, lacrosse, and skiing. Researchers say that a woman's body causes her to land from a jump with more flex in the ankle and more foot rollout, which puts stress on the knee. Loose knee joints and other differences between the male and female body may add to the risk, along with hormone levels.

Stress fractures, kneecap pain, and foot deformities are also more common in females, says Anne Z. Hoch, D.O., a women's sports medicine specialist in Milwaukee.

The 'triad'

One threat unique to women is the "female athlete triad," a condition marked by eating disorders, amenorrhea (missed periods), and osteoporosis. In the late 1980s, when Dr. Toth played basketball for Yale, she and her teammates viewed it a badge of honor if their periods stopped. They felt it proved that they were working out hard. But the condition, while common, is not healthy or normal.

The female athlete triad starts with nutritional issues. An active woman may cut back on calories to lose weight, or she may burn more calories exercising than she's taking in. Crash dieting and binge eating are other signs of a possible eating disorder. Any of these can create a calorie deficit that affects total body fat and, subsequently, the reproductive system, leading to low estrogen levels and missed periods.

Calorie deficit

"Typically, we see girls with daily calorie deficits of 1,000 to 1,500 calories," Dr. Hoch says. Just to get through the day, a girl needs 1,500 to 1,800 calories. "You need 100 calories more for every mile you run. So if you run five to 10 miles, you need to add another 500 to 1,000 calories. But instead of taking in 2,500 calories, some of these girls are only taking in 1,000 or 1,500 calories."

The athletes' low estrogen levels and missed periods are linked to osteoporosis. Estrogen helps the body use calcium and maintain normal bone metabolism. Missing three or more periods in a row is usually a sign that there may not be sufficient estrogen to build and maintain bone density. Over time this decrease of estrogen can lead to weakened bones. One sign of decreased bone density are stress fractures. A return to a normal menstrual cycle may help recover much, but not all of the lost bone density.

Another cause of decreased bone density can be too little calcium and vitamin D during preteen and teen years. Females should develop most of their bone mass and highest bone density during their teens. Yet Dr. Hoch quotes federal government research showing that just 13 percent of girls ages 11 to 14 get enough calcium. Teens and older women need to supplement the calcium and vitamin D if they don't get enough in their diet.

Circulation problems

Research by Dr. Hoch also found that female triad athletes face a greater risk for premature circulation problems. Tests showed college runners whose periods have stopped had hardening of the arteries.

Any female athlete is at risk for the triad. But Dr. Hoch says it's most common in sports that require girls to be thin, such as runners, ballerinas, gymnasts, and figure skaters, whose sports focus more on appearance and weight.

Treatment often involves a team approach, like the one Dr. Hoch's program offers. A doctor, nutritionist, and psychologist work with the athlete, her coach, and her parents. Full recovery can take months, even years.

"Our studies on amenorrheic athletes have found that when girls improve their diets and fuel their bodies properly, they gain weight and body fat and their menstrual periods return," says Dr. Hoch. "Yet, we also see an improvement in their 5-kilometer running times. So it's a win-win situation."